WASHINGTON – A $1,000-per-pill drug that insurers are reluctant to pay for has quickly become the treatment of choice for a liver-wasting viral disease that affects more than 3 million Americans.

In less than six months, prescriptions for Sovaldi have eclipsed all other hepatitis C pills combined, according to new data from IMS Health. The prospect of a real cure, with fewer nasty side effects, is enticing thousands of patients to get treated for the first time.

But clinical and commercial successes have triggered scrutiny for the drug’s manufacturer, California-based Gilead Sciences Inc., which just reported second-quarter profits of $3.66 billion, a net margin of 56 percent.

Two senior senators are raising questions about documents that suggest the initial developers of Sovaldi considered pricing treatment at less than half as much. The health insurance industry is publicly scolding Gilead, and state Medicaid programs that provide health coverage for the poor are pushing back.

The repercussions for patients could go beyond one drug and one disease.

A number of promising cancer medications near approval could provide the next storm over costs. The average cost of brand-name cancer drugs has doubled in a decade, to about $10,000 a month.

“You can’t put too fine a point on the sort of moral dilemma that we have here,” said Michael Kleinrock, director of the IMS Institute, which studies prescription drug trends. “This is something that the research-based pharmaceutical industry reaches for all the time: A cure. But when they achieve one, can we afford it?”

What it’s done

New data from IMS Health, the Connecticut parent company of the institute, illustrate Sovaldi’s effect since its debut in December:

• The total number of pharmacy prescriptions for all hepatitis C pills has soared, highlighting patient demand for a cure. In May, more than 48,000 prescriptions were filled for four such medications, with Sovaldi accounting for three-fourths of the total. By comparison, prescriptions for May 2013 totaled about 6,200. That was before Sovaldi became available.

• In Sovaldi’s first 30 weeks on the market, 62,000 new patients tried the drug, nearly three times as many as had tried an earlier medication that showed promise.

• The weekly number of new patients going on Sovaldi has been gradually slowing. That could indicate that initial demand is giving way to steadier levels, or it could mean that insurers are limiting access to protect their budgets.

Cooperation

Sovaldi’s implications for Medicare and Medicaid costs have prompted rare bipartisan cooperation in Congress on a health care issue.

Democratic Sen. Ron Wyden and Republican Sen. Charles Grassley are asking Gilead for a detailed explanation of its pricing. Wyden chairs the Finance Committee, which oversees health insurance programs, and Grassley is a veteran of drug safety investigations.

The senators say their staffs unearthed information from public documents that calls into question Gilead’s $84,000 price for a full course of Sovaldi treatment, for the most common type of hepatitis C.

In 2011 filings with federal market regulators, the company that originally developed Sovaldi estimated a price of $36,000. That number was developed during Gilead’s negotiations to buy Pharmasset, the original developer.

Gilead spokeswoman Amy Flood said the company has no comment.

Company response

But Gilead Vice President Gregg Alton recently addressed the issue at a public forum sponsored by the American Enterprise Institute, a think tank.

Gilead took on most of the challenge — and risk — of getting government approval for Sovaldi, he said.

Alton suggested another standard for measuring the value of Sovaldi, something called “cost-per-cure.” As he explained it, that makes Sovaldi look like a bargain.

The older hepatitis C treatment regimens take longer and are less effective, and Alton estimated their cost-per-cure at somewhere between $150,000 and $200,000.

“With a Sovaldi regimen we’re actually getting down to $115,000 per cure,” said Alton. “So it is actually, on a per-cure basis, much less costly.”

ABOUT THE DISEASE

Hepatitis C surpassed AIDS as a cause of death in the U.S. in 2007, claiming an estimated 15,000 lives that year. The illness is complex, with distinct virus types requiring different treatments. While it advances gradually, it can ultimately destroy the liver, and transplants average $577,000.